Will the SCT 3015 effect emissions,in other words shoud i return it to tune for emmisions.

Also the 3 settings are 89,91,93 octane around our area all we have is 89 and 93.My question is can i do the 91 setting with 89 octane gas

Also will the settings effect shifting at different intervals

Reason im asking is SCT takes all day to get through

 

sorry we have 87 and 91 octane can i use the 89 setting with 87 octane

 

NO, you will destroy your engine, ALWAYS put the same or higher octane gas in your car than the tune.

87 gas, only 87 tune.

IMO if you're spending money to buy a tuner and want performance gains, use the highest octane gas, I'm using 93.